1. Field of the Invention
The present invention relates to agricultural irrigation systems. More particularly, the invention relates to a control system for stopping and/or reversing movement of an irrigation system.
2. Background
Agricultural irrigation systems such as central pivot irrigation machines and lateral move irrigation machines are commonly used to irrigate crops. A central pivot irrigation machine typically includes, among other things, a central pivot communicating with a pressurized water supply and a series of spans formed from mobile support towers connected to the central pivot and to one another by truss-type framework sections. The mobile support towers are supported on wheels that are driven by a motor on each tower. A water distribution conduit is supported by the framework sections and a number of sprinkler heads, spray guns, drop nozzles, or other fluid-emitting devices are spaced along the length of the conduit. A lateral move irrigation system is similar except it does not include a central pivot but instead has several aligned spans that move laterally across a rectangular-shaped field.
Irrigation systems must be stopped and/or reversed when they reach the end of an area to be irrigated or an obstacle such as a building tree, road, etc. To do so, a typical irrigation system includes a quill or rod extending from one of its towers and a barrier positioned near a boundary of the area being irrigated. When the irrigation system approaches the boundary, the quill or rod touches the barrier and shifts positions to operate a switch. The switch then stops and/or reverses the direction of the irrigation system.
Unfortunately, the quills and barriers are relatively expensive and difficult to install. Moreover, the barrier can block movement of tractors and other vehicles that need access to the area being irrigated, and the quills or rods are occasionally tripped by tree branches, tall crops, and other objects in the path of the irrigation system. This may result in inadvertent stopping and/or reversing of the irrigation system and thus over-watering of some areas and under watering of others.